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Seawater Module Documentation

This module provides functions to calculate various seawater properties.

Functions:

Name Description
ctd2svel

Calculate sound velocity from conductivity, temperature, and depth.
depth2pressure

Calculate pressure from depth.
ctp2salinity

Calculate absolute salinity from conductivity, temperature, and pressure.
ctd2salinity

Calculate absolute salinity from conductivity, temperature, and depth.
ctp2pden

Calculate potential density from conductivity, temperature, and pressure.
ctd2oxygen_saturation

Calculate oxygen saturation from conductivity, temperature, and depth.

Calculates the oxygen saturation value (ml/l) from salinity and temperature.

Calculates the oxygen concentration expected at equilibrium with air at an Absolute Pressure of 101325 Pa (sea pressure of 0 dbar) including saturated water vapor. This function uses the solubility coefficients derived from the data of Benson and Krause (1984), as fitted by Garcia and Gordon (1992, 1993).

Parameters:

Name Type Description Default
conductivity Union[float, ndarray, List[float]]

Conductivity in S/m.

 required
temperature Union[float, ndarray, List[float]]

Temperature in degrees Celsius (ITS-90).

 required
depth Union[float, ndarray, List[float]]

Depth in meters. Positive is upward.

 required
latitude Union[float, ndarray, List[float]]

Latitude in degrees. Defaults to None.

 None
longitude Union[float, ndarray, List[float]]

Longitude in degrees. Defaults to None.

 None

Returns:

Name Type Description
solubility Union[float, ndarray]

Solubility of oxygen in micro-moles per kg

Raises:

Type Description
TypeError

If the inputs are not of the correct type.
ValueError

If the inputs are not of the correct shape or range.
Source code in navlib/environment/seawater.py 
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def ctd2oxygen_saturation(
    conductivity: Union[float, np.ndarray, List[float]],
    temperature: Union[float, np.ndarray, List[float]],
    depth: Union[float, np.ndarray, List[float]],
    latitude: Union[float, np.ndarray, List[float]] = None,
    longitude: Union[float, np.ndarray, List[float]] = None,
) -> Union[float, np.ndarray]:
    """
    Calculates the oxygen saturation value (ml/l) from salinity and temperature.

    Calculates the oxygen concentration expected at equilibrium with air at an
    Absolute Pressure of 101325 Pa (sea pressure of 0 dbar) including saturated
    water vapor. This function uses the solubility coefficients derived from the
    data of Benson and Krause (1984), as fitted by Garcia and Gordon (1992, 1993).

    Args:
        conductivity (Union[float, np.ndarray, List[float]]): Conductivity in S/m.
        temperature (Union[float, np.ndarray, List[float]]): Temperature in degrees Celsius (ITS-90).
        depth (Union[float, np.ndarray, List[float]]): Depth in meters. Positive is upward.
        latitude (Union[float, np.ndarray, List[float]], optional): Latitude in degrees. Defaults to None.
        longitude (Union[float, np.ndarray, List[float]], optional): Longitude in degrees. Defaults to None.

    Returns:
        solubility (Union[float, np.ndarray]): Solubility of oxygen in micro-moles per kg

    Raises:
        TypeError: If the inputs are not of the correct type.
        ValueError: If the inputs are not of the correct shape or range.
    """
    # Convert to numpy arrays
    if isinstance(conductivity, list):
        conductivity = np.array(conductivity)
    if isinstance(temperature, list):
        temperature = np.array(temperature)
    if isinstance(depth, list):
        depth = np.array(depth)
    if isinstance(latitude, list):
        latitude = np.array(latitude)
    if isinstance(longitude, list):
        longitude = np.array(longitude)

    # Check inputs type
    if not isinstance(conductivity, (np.ndarray, float)):
        raise TypeError("Conductivity must be a float or an array.")
    if not isinstance(temperature, (np.ndarray, float)):
        raise TypeError("Temperature must be a float or an array.")
    if not isinstance(depth, (np.ndarray, float)):
        raise TypeError("Depth must be a float or an array.")
    if latitude is not None and not isinstance(latitude, (np.ndarray, float)):
        raise TypeError("Latitude must be a float or an array.")
    if longitude is not None and not isinstance(longitude, (np.ndarray, float)):
        raise TypeError("Longitude must be a float or an array.")

    # Check shape of inputs if they are numpy arrays
    if isinstance(conductivity, np.ndarray):
        conductivity = conductivity.squeeze()
        if conductivity.ndim > 1:
            raise ValueError("Conductivity must be a 1D array.")
    if isinstance(temperature, np.ndarray):
        temperature = temperature.squeeze()
        if temperature.ndim > 1:
            raise ValueError("Temperature must be a 1D array.")
    if isinstance(depth, np.ndarray):
        depth = depth.squeeze()
        if depth.ndim > 1:
            raise ValueError("Depth must be a 1D array.")
    if latitude is not None and isinstance(latitude, np.ndarray):
        latitude = latitude.squeeze()
        if latitude.ndim > 1:
            raise ValueError("Latitude must be a 1D array.")
    if longitude is not None and isinstance(longitude, np.ndarray):
        longitude = longitude.squeeze()
        if longitude.ndim > 1:
            raise ValueError("Longitude must be a 1D array.")

    # If latitude is not provided, set it to 0
    if latitude is None:
        latitude = 0 if isinstance(depth, float) else np.zeros_like(depth)
    elif isinstance(latitude, float) and isinstance(depth, np.ndarray):
        latitude = np.full_like(depth, latitude)

    # If longitude is not provided, set it to 0
    if longitude is None:
        longitude = 0 if isinstance(depth, float) else np.zeros_like(depth)
    elif isinstance(longitude, float) and isinstance(depth, np.ndarray):
        longitude = np.full_like(depth, longitude)

    # Check that the inputs are of the same shape
    if isinstance(conductivity, np.ndarray):
        if (
            conductivity.shape != temperature.shape
            or conductivity.shape != depth.shape
            or conductivity.shape != latitude.shape
            or conductivity.shape != longitude.shape
        ):
            raise ValueError(
                "Conductivity, temperature, depth, latitude, and longitude must have the same shape."
            )

    # Check that the depth is negative
    if isinstance(depth, np.ndarray):
        if np.any(depth > 0):
            raise ValueError("Depth must be negative.")
    else:
        if depth > 0:
            raise ValueError("Depth must be negative.")

    # Check that the latitude is between -90 and 90
    if isinstance(latitude, np.ndarray):
        if np.any(latitude < -90) or np.any(latitude > 90):
            raise ValueError("Latitude must be between -90 and 90 degrees.")
    else:
        if latitude < -90 or latitude > 90:
            raise ValueError("Latitude must be between -90 and 90 degrees.")

    # Check that the longitude is between -360 and 360
    if isinstance(longitude, np.ndarray):
        if np.any(longitude < -360) or np.any(longitude > 360):
            raise ValueError("Longitude must be between -360 and 360 degrees.")
    else:
        if longitude < -360 or longitude > 360:
            raise ValueError("Longitude must be between -360 and 360 degrees.")

    # Calculate sound velocity
    pressure = gsw.p_from_z(depth, latitude)
    practical_salinity = gsw.SP_from_C(conductivity, temperature, pressure)
    absolute_salinity = gsw.SA_from_SP(
        practical_salinity, pressure, longitude, latitude
    )
    conservative_temperature = gsw.CT_from_t(absolute_salinity, temperature, pressure)
    o2sol = gsw.O2sol(
        absolute_salinity, conservative_temperature, pressure, longitude, latitude
    )
    return o2sol

Calculates absolute salinity in g/kg from conductivity, temperature, and depth.

Parameters:

Name Type Description Default
conductivity Union[float, ndarray, List[float]]

Conductivity in S/m.

 required
temperature Union[float, ndarray, List[float]]

Temperature in degrees Celsius (ITS-90).

 required
depth Union[float, ndarray, List[float]]

Depth in meters. Positive is upward.

 required
latitude Union[float, ndarray, List[float]]

Latitude in degrees. Defaults to None.

 None
longitude Union[float, ndarray, List[float]]

Longitude in degrees. Defaults to None.

 None

Raises:

Type Description
TypeError

If the inputs are not of the correct type.
ValueError

If the inputs are not of the correct shape or range.
Source code in navlib/environment/seawater.py 
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def ctd2salinity(
    conductivity: Union[float, np.ndarray, List[float]],
    temperature: Union[float, np.ndarray, List[float]],
    depth: Union[float, np.ndarray, List[float]],
    latitude: Union[float, np.ndarray, List[float]] = None,
    longitude: Union[float, np.ndarray, List[float]] = None,
) -> Union[float, np.ndarray]:
    """
    Calculates absolute salinity in g/kg from conductivity, temperature, and depth.

    Args:
        conductivity (Union[float, np.ndarray, List[float]]): Conductivity in S/m.
        temperature (Union[float, np.ndarray, List[float]]): Temperature in degrees Celsius (ITS-90).
        depth (Union[float, np.ndarray, List[float]]): Depth in meters. Positive is upward.
        latitude (Union[float, np.ndarray, List[float]], optional): Latitude in degrees. Defaults to None.
        longitude (Union[float, np.ndarray, List[float]], optional): Longitude in degrees. Defaults to None.
    Returns:
        absolute_salinity (Union[float, np.ndarray]): Absolute salinity in g/kg.

    Raises:
        TypeError: If the inputs are not of the correct type.
        ValueError: If the inputs are not of the correct shape or range.
    """
    # Convert to numpy arrays
    if isinstance(conductivity, list):
        conductivity = np.array(conductivity)
    if isinstance(temperature, list):
        temperature = np.array(temperature)
    if isinstance(depth, list):
        depth = np.array(depth)
    if isinstance(latitude, list):
        latitude = np.array(latitude)
    if isinstance(longitude, list):
        longitude = np.array(longitude)

    # Check inputs type
    if not isinstance(conductivity, (np.ndarray, float)):
        raise TypeError("Conductivity must be a float or an array.")
    if not isinstance(temperature, (np.ndarray, float)):
        raise TypeError("Temperature must be a float or an array.")
    if not isinstance(depth, (np.ndarray, float)):
        raise TypeError("Depth must be a float or an array.")
    if latitude is not None and not isinstance(latitude, (np.ndarray, float)):
        raise TypeError("Latitude must be a float or an array.")
    if longitude is not None and not isinstance(longitude, (np.ndarray, float)):
        raise TypeError("Longitude must be a float or an array.")

    # Check shape of inputs if they are numpy arrays
    if isinstance(conductivity, np.ndarray):
        conductivity = conductivity.squeeze()
        if conductivity.ndim > 1:
            raise ValueError("Conductivity must be a 1D array.")
    if isinstance(temperature, np.ndarray):
        temperature = temperature.squeeze()
        if temperature.ndim > 1:
            raise ValueError("Temperature must be a 1D array.")
    if isinstance(depth, np.ndarray):
        depth = depth.squeeze()
        if depth.ndim > 1:
            raise ValueError("Depth must be a 1D array.")
    if latitude is not None and isinstance(latitude, np.ndarray):
        latitude = latitude.squeeze()
        if latitude.ndim > 1:
            raise ValueError("Latitude must be a 1D array.")
    if longitude is not None and isinstance(longitude, np.ndarray):
        longitude = longitude.squeeze()
        if longitude.ndim > 1:
            raise ValueError("Longitude must be a 1D array.")

    # If latitude is not provided, set it to 0
    if latitude is None:
        latitude = 0 if isinstance(depth, float) else np.zeros_like(depth)
    elif isinstance(latitude, float) and isinstance(depth, np.ndarray):
        latitude = np.full_like(depth, latitude)

    # If longitude is not provided, set it to 0
    if longitude is None:
        longitude = 0 if isinstance(depth, float) else np.zeros_like(depth)
    elif isinstance(longitude, float) and isinstance(depth, np.ndarray):
        longitude = np.full_like(depth, longitude)

    # Check that the inputs are of the same shape
    if isinstance(conductivity, np.ndarray):
        if (
            conductivity.shape != temperature.shape
            or conductivity.shape != depth.shape
            or conductivity.shape != latitude.shape
            or conductivity.shape != longitude.shape
        ):
            raise ValueError(
                "Conductivity, temperature, depth, latitude, and longitude must have the same shape."
            )

    # Check that the depth is negative
    if isinstance(depth, np.ndarray):
        if np.any(depth > 0):
            raise ValueError("Depth must be negative.")
    else:
        if depth > 0:
            raise ValueError("Depth must be negative.")

    # Check that the latitude is beetwen -90 and 90
    if isinstance(latitude, np.ndarray):
        if np.any(latitude < -90) or np.any(latitude > 90):
            raise ValueError("Latitude must be between -90 and 90 degrees.")
    else:
        if latitude < -90 or latitude > 90:
            raise ValueError("Latitude must be between -90 and 90 degrees.")

    # Check that the longitude is beetwen -360 and 360
    if isinstance(longitude, np.ndarray):
        if np.any(longitude < -360) or np.any(longitude > 360):
            raise ValueError("Longitude must be between -360 and 360 degrees.")
    else:
        if longitude < -360 or longitude > 360:
            raise ValueError("Longitude must be between -360 and 360 degrees.")

    # Calculate sound velocity
    pressure = gsw.p_from_z(depth, latitude)
    practical_salinity = gsw.SP_from_C(conductivity, temperature, pressure)
    absolute_salinity = gsw.SA_from_SP(
        practical_salinity, pressure, longitude, latitude
    )
    return absolute_salinity

Calculates sound velocity in m/s from conductivity, temperature, and depth.

Parameters:

Name Type Description Default
conductivity Union[float, ndarray, List[float]]

Conductivity in S/m.

 required
temperature Union[float, ndarray, List[float]]

Temperature in degrees Celsius (ITS-90).

 required
depth Union[float, ndarray, List[float]]

Depth in meters. Positive is upward.

 required
latitude Union[float, ndarray, List[float]]

Latitude in degrees. Defaults to None.

 None
longitude Union[float, ndarray, List[float]]

Longitude in degrees. Defaults to None.

 None

Raises:

Type Description
TypeError

If the inputs are not of the correct type.
ValueError

If the inputs are not of the correct shape or range.
Source code in navlib/environment/seawater.py 
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def ctd2svel(
    conductivity: Union[float, np.ndarray, List[float]],
    temperature: Union[float, np.ndarray, List[float]],
    depth: Union[float, np.ndarray, List[float]],
    latitude: Union[float, np.ndarray, List[float]] = None,
    longitude: Union[float, np.ndarray, List[float]] = None,
) -> Union[float, np.ndarray]:
    """
    Calculates sound velocity in m/s from conductivity, temperature, and depth.

    Args:
        conductivity (Union[float, np.ndarray, List[float]]): Conductivity in S/m.
        temperature (Union[float, np.ndarray, List[float]]): Temperature in degrees Celsius (ITS-90).
        depth (Union[float, np.ndarray, List[float]]): Depth in meters. Positive is upward.
        latitude (Union[float, np.ndarray, List[float]], optional): Latitude in degrees. Defaults to None.
        longitude (Union[float, np.ndarray, List[float]], optional): Longitude in degrees. Defaults to None.
    Returns:
        sound_velocity (Union[float, np.ndarray]): Sound velocity in m/s.

    Raises:
        TypeError: If the inputs are not of the correct type.
        ValueError: If the inputs are not of the correct shape or range.
    """
    # Convert to numpy arrays
    if isinstance(conductivity, list):
        conductivity = np.array(conductivity)
    if isinstance(temperature, list):
        temperature = np.array(temperature)
    if isinstance(depth, list):
        depth = np.array(depth)
    if isinstance(latitude, list):
        latitude = np.array(latitude)
    if isinstance(longitude, list):
        longitude = np.array(longitude)

    # Check inputs type
    if not isinstance(conductivity, (np.ndarray, float)):
        raise TypeError("Conductivity must be a float or an array.")
    if not isinstance(temperature, (np.ndarray, float)):
        raise TypeError("Temperature must be a float or an array.")
    if not isinstance(depth, (np.ndarray, float)):
        raise TypeError("Depth must be a float or an array.")
    if latitude is not None and not isinstance(latitude, (np.ndarray, float)):
        raise TypeError("Latitude must be a float or an array.")
    if longitude is not None and not isinstance(longitude, (np.ndarray, float)):
        raise TypeError("Longitude must be a float or an array.")

    # Check shape of inputs if they are numpy arrays
    if isinstance(conductivity, np.ndarray):
        conductivity = conductivity.squeeze()
        if conductivity.ndim > 1:
            raise ValueError("Conductivity must be a 1D array.")
    if isinstance(temperature, np.ndarray):
        temperature = temperature.squeeze()
        if temperature.ndim > 1:
            raise ValueError("Temperature must be a 1D array.")
    if isinstance(depth, np.ndarray):
        depth = depth.squeeze()
        if depth.ndim > 1:
            raise ValueError("Depth must be a 1D array.")
    if latitude is not None and isinstance(latitude, np.ndarray):
        latitude = latitude.squeeze()
        if latitude.ndim > 1:
            raise ValueError("Latitude must be a 1D array.")
    if longitude is not None and isinstance(longitude, np.ndarray):
        longitude = longitude.squeeze()
        if longitude.ndim > 1:
            raise ValueError("Longitude must be a 1D array.")

    # If latitude is not provided, set it to 0
    if latitude is None:
        latitude = 0 if isinstance(depth, float) else np.zeros_like(depth)
    elif isinstance(latitude, float) and isinstance(depth, np.ndarray):
        latitude = np.full_like(depth, latitude)

    # If longitude is not provided, set it to 0
    if longitude is None:
        longitude = 0 if isinstance(depth, float) else np.zeros_like(depth)
    elif isinstance(longitude, float) and isinstance(depth, np.ndarray):
        longitude = np.full_like(depth, longitude)

    # Check that the inputs are of the same shape
    if isinstance(conductivity, np.ndarray):
        if (
            conductivity.shape != temperature.shape
            or conductivity.shape != depth.shape
            or conductivity.shape != latitude.shape
            or conductivity.shape != longitude.shape
        ):
            raise ValueError(
                "Conductivity, temperature, depth, latitude, and longitude must have the same shape."
            )

    # Check that the depth is negative
    if isinstance(depth, np.ndarray):
        if np.any(depth > 0):
            raise ValueError("Depth must be negative.")
    else:
        if depth > 0:
            raise ValueError("Depth must be negative.")

    # Check that the latitude is between -90 and 90
    if isinstance(latitude, np.ndarray):
        if np.any(latitude < -90) or np.any(latitude > 90):
            raise ValueError("Latitude must be between -90 and 90 degrees.")
    else:
        if latitude < -90 or latitude > 90:
            raise ValueError("Latitude must be between -90 and 90 degrees.")

    # Check that the longitude is between -360 and 360
    if isinstance(longitude, np.ndarray):
        if np.any(longitude < -360) or np.any(longitude > 360):
            raise ValueError("Longitude must be between -360 and 360 degrees.")
    else:
        if longitude < -360 or longitude > 360:
            raise ValueError("Longitude must be between -360 and 360 degrees.")

    # Calculate sound velocity
    pressure = gsw.p_from_z(depth, latitude)
    practical_salinity = gsw.SP_from_C(conductivity, temperature, pressure)
    absolute_salinity = gsw.SA_from_SP(
        practical_salinity, pressure, longitude, latitude
    )
    conservative_temperature = gsw.CT_from_t(absolute_salinity, temperature, pressure)
    sound_speed = gsw.sound_speed(absolute_salinity, conservative_temperature, pressure)
    return sound_speed

Calculates potential density (kg/m^3) relative to a reference pressure (default 0 dbar) from conductivity, temperature, and pressure using the gsw library.

Parameters:

Name Type Description Default
conductivity Union[float, ndarray, List[float]]

Conductivity in S/m.

 required
temperature Union[float, ndarray, List[float]]

Temperature in degrees Celsius (ITS-90).

 required
pressure Union[float, ndarray, List[float]]

Pressure in dbars.

 required
latitude Union[float, ndarray, List[float]]

Latitude in degrees. Defaults to None.

 None
longitude Union[float, ndarray, List[float]]

Longitude in degrees. Defaults to None.

 None
pressure_reference Union[float, ndarray, List[float]]

Reference pressure in dbars. Defaults to None.

 None

Returns:

Name Type Description
potential_density Union[float, ndarray]

Potential density in kg/m^3.

Raises:

Type Description
TypeError

If the inputs are not of the correct type.
ValueError

If the inputs are not of the correct shape or range.
Source code in navlib/environment/seawater.py 
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def ctp2pden(
    conductivity: Union[float, np.ndarray, List[float]],
    temperature: Union[float, np.ndarray, List[float]],
    pressure: Union[float, np.ndarray, List[float]],
    latitude: Union[float, np.ndarray, List[float]] = None,
    longitude: Union[float, np.ndarray, List[float]] = None,
    pressure_reference: Union[float, np.ndarray, List[float]] = None,
) -> Union[float, np.ndarray]:
    """
    Calculates potential density (kg/m^3) relative to a reference pressure
    (default 0 dbar) from conductivity, temperature, and pressure using the gsw library.

    Args:
        conductivity (Union[float, np.ndarray, List[float]]): Conductivity in S/m.
        temperature (Union[float, np.ndarray, List[float]]): Temperature in degrees Celsius (ITS-90).
        pressure (Union[float, np.ndarray, List[float]]): Pressure in dbars.
        latitude (Union[float, np.ndarray, List[float]], optional): Latitude in degrees. Defaults to None.
        longitude (Union[float, np.ndarray, List[float]], optional): Longitude in degrees. Defaults to None.
        pressure_reference (Union[float, np.ndarray, List[float]], optional): Reference pressure in dbars. Defaults to None.

    Returns:
        potential_density (Union[float, np.ndarray]): Potential density in kg/m^3.

    Raises:
        TypeError: If the inputs are not of the correct type.
        ValueError: If the inputs are not of the correct shape or range.
    """
    # Convert to numpy arrays
    if isinstance(conductivity, list):
        conductivity = np.array(conductivity)
    if isinstance(temperature, list):
        temperature = np.array(temperature)
    if isinstance(pressure, list):
        pressure = np.array(pressure)
    if isinstance(latitude, list):
        latitude = np.array(latitude)
    if isinstance(longitude, list):
        longitude = np.array(longitude)
    if isinstance(pressure_reference, list):
        pressure_reference = np.array(pressure_reference)

    # Check inputs type
    if not isinstance(conductivity, (np.ndarray, float)):
        raise TypeError("Conductivity must be a float or an array.")
    if not isinstance(temperature, (np.ndarray, float)):
        raise TypeError("Temperature must be a float or an array.")
    if not isinstance(pressure, (np.ndarray, float)):
        raise TypeError("Pressure must be a float or an array.")
    if latitude is not None and not isinstance(latitude, (np.ndarray, float)):
        raise TypeError("Latitude must be a float or an array.")
    if longitude is not None and not isinstance(longitude, (np.ndarray, float)):
        raise TypeError("Longitude must be a float or an array.")
    if pressure_reference is not None and not isinstance(
        pressure_reference, (np.ndarray, float)
    ):
        raise TypeError("Pressure reference must be a float or an array.")

    # Check shape of inputs if they are numpy arrays
    if isinstance(conductivity, np.ndarray):
        conductivity = conductivity.squeeze()
        if conductivity.ndim > 1:
            raise ValueError("Conductivity must be a 1D array.")
    if isinstance(temperature, np.ndarray):
        temperature = temperature.squeeze()
        if temperature.ndim > 1:
            raise ValueError("Temperature must be a 1D array.")
    if isinstance(pressure, np.ndarray):
        pressure = pressure.squeeze()
        if pressure.ndim > 1:
            raise ValueError("Pressure must be a 1D array.")
    if latitude is not None and isinstance(latitude, np.ndarray):
        latitude = latitude.squeeze()
        if latitude.ndim > 1:
            raise ValueError("Latitude must be a 1D array.")
    if longitude is not None and isinstance(longitude, np.ndarray):
        longitude = longitude.squeeze()
        if longitude.ndim > 1:
            raise ValueError("Longitude must be a 1D array.")
    if pressure_reference is not None and isinstance(pressure_reference, np.ndarray):
        pressure_reference = pressure_reference.squeeze()
        if pressure_reference.ndim > 1:
            raise ValueError("Pressure reference must be a 1D array.")

    # If latitude is not provided, set it to 0
    if latitude is None:
        latitude = 0 if isinstance(pressure, float) else np.zeros_like(pressure)
    elif isinstance(latitude, float) and isinstance(pressure, np.ndarray):
        latitude = np.full_like(pressure, latitude)

    # If longitude is not provided, set it to 0
    if longitude is None:
        longitude = 0 if isinstance(pressure, float) else np.zeros_like(pressure)
    elif isinstance(longitude, float) and isinstance(pressure, np.ndarray):
        longitude = np.full_like(pressure, longitude)

    # If pressure reference is not provided, set it to 0
    if pressure_reference is None:
        pressure_reference = (
            0 if isinstance(pressure, float) else np.zeros_like(pressure)
        )
    elif isinstance(pressure_reference, float) and isinstance(pressure, np.ndarray):
        pressure_reference = np.full_like(pressure, pressure_reference)

    # Check that the inputs are of the same shape
    if isinstance(conductivity, np.ndarray):
        if (
            conductivity.shape != temperature.shape
            or conductivity.shape != pressure.shape
            or conductivity.shape != latitude.shape
            or conductivity.shape != longitude.shape
            or conductivity.shape != pressure_reference.shape
        ):
            raise ValueError(
                "Conductivity, temperature, pressure, latitude, longitude and reference pressure must have the same shape."
            )

    # Check that the latitude is beetwen -90 and 90
    if isinstance(latitude, np.ndarray):
        if np.any(latitude < -90) or np.any(latitude > 90):
            raise ValueError("Latitude must be between -90 and 90 degrees.")
    else:
        if latitude < -90 or latitude > 90:
            raise ValueError("Latitude must be between -90 and 90 degrees.")

    # Check that the longitude is beetwen -360 and 360
    if isinstance(longitude, np.ndarray):
        if np.any(longitude < -360) or np.any(longitude > 360):
            raise ValueError("Longitude must be between -360 and 360 degrees.")
    else:
        if longitude < -360 or longitude > 360:
            raise ValueError("Longitude must be between -360 and 360 degrees.")

    # Compute potential density using the exact potential density function
    practical_salinity = gsw.SP_from_C(conductivity, temperature, pressure)
    absolute_salinity = gsw.SA_from_SP(
        practical_salinity, pressure, longitude, latitude
    )
    pden = gsw.pot_rho_t_exact(
        absolute_salinity, temperature, pressure, pressure_reference
    )
    return pden

Calculates absolute salinity in g/kg from conductivity, temperature, and pressure.

Args: conductivity (Union[float, np.ndarray, List[float]]): Conductivity in S/m. temperature (Union[float, np.ndarray, List[float]]): Temperature in degrees Celsius (ITS-90). pressure (Union[float, np.ndarray, List[float]]): Pressure in dbars. latitude (Union[float, np.ndarray, List[float]], optional): Latitude in degrees. Defaults to None. longitude (Union[float, np.ndarray, List[float]], optional): Longitude in degrees. Defaults to None.

Returns:

Name Type Description
absolute_salinity Union[float, ndarray]

Absolute salinity in g/kg.

Raises:

Type Description
TypeError

If the inputs are not of the correct type.
ValueError

If the inputs are not of the correct shape or range.
Source code in navlib/environment/seawater.py 
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def ctp2salinity(
    conductivity: Union[float, np.ndarray, List[float]],
    temperature: Union[float, np.ndarray, List[float]],
    pressure: Union[float, np.ndarray, List[float]],
    latitude: Union[float, np.ndarray, List[float]] = None,
    longitude: Union[float, np.ndarray, List[float]] = None,
) -> Union[float, np.ndarray]:
    """
     Calculates absolute salinity in g/kg from conductivity, temperature, and pressure.

     Args:
        conductivity (Union[float, np.ndarray, List[float]]): Conductivity in S/m.
        temperature (Union[float, np.ndarray, List[float]]): Temperature in degrees Celsius (ITS-90).
        pressure (Union[float, np.ndarray, List[float]]): Pressure in dbars.
        latitude (Union[float, np.ndarray, List[float]], optional): Latitude in degrees. Defaults to None.
        longitude (Union[float, np.ndarray, List[float]], optional): Longitude in degrees. Defaults to None.

    Returns:
        absolute_salinity (Union[float, np.ndarray]): Absolute salinity in g/kg.

    Raises:
        TypeError: If the inputs are not of the correct type.
        ValueError: If the inputs are not of the correct shape or range.
    """
    # Convert to numpy arrays
    if isinstance(conductivity, list):
        conductivity = np.array(conductivity)
    if isinstance(temperature, list):
        temperature = np.array(temperature)
    if isinstance(pressure, list):
        pressure = np.array(pressure)
    if isinstance(latitude, list):
        latitude = np.array(latitude)
    if isinstance(longitude, list):
        longitude = np.array(longitude)

    # Check inputs type
    if not isinstance(conductivity, (np.ndarray, float)):
        raise TypeError("Conductivity must be a float or an array.")
    if not isinstance(temperature, (np.ndarray, float)):
        raise TypeError("Temperature must be a float or an array.")
    if not isinstance(pressure, (np.ndarray, float)):
        raise TypeError("Pressure must be a float or an array.")
    if latitude is not None and not isinstance(latitude, (np.ndarray, float)):
        raise TypeError("Latitude must be a float or an array.")
    if longitude is not None and not isinstance(longitude, (np.ndarray, float)):
        raise TypeError("Longitude must be a float or an array.")

    # Check shape of inputs if they are numpy arrays
    if isinstance(conductivity, np.ndarray):
        conductivity = conductivity.squeeze()
        if conductivity.ndim > 1:
            raise ValueError("Conductivity must be a 1D array.")
    if isinstance(temperature, np.ndarray):
        temperature = temperature.squeeze()
        if temperature.ndim > 1:
            raise ValueError("Temperature must be a 1D array.")
    if isinstance(pressure, np.ndarray):
        pressure = pressure.squeeze()
        if pressure.ndim > 1:
            raise ValueError("Pressure must be a 1D array.")
    if latitude is not None and isinstance(latitude, np.ndarray):
        latitude = latitude.squeeze()
        if latitude.ndim > 1:
            raise ValueError("Latitude must be a 1D array.")
    if longitude is not None and isinstance(longitude, np.ndarray):
        longitude = longitude.squeeze()
        if longitude.ndim > 1:
            raise ValueError("Longitude must be a 1D array.")

    # If latitude is not provided, set it to 0
    if latitude is None:
        latitude = 0 if isinstance(pressure, float) else np.zeros_like(pressure)
    elif isinstance(latitude, float) and isinstance(pressure, np.ndarray):
        latitude = np.full_like(pressure, latitude)

    # If longitude is not provided, set it to 0
    if longitude is None:
        longitude = 0 if isinstance(pressure, float) else np.zeros_like(pressure)
    elif isinstance(longitude, float) and isinstance(pressure, np.ndarray):
        longitude = np.full_like(pressure, longitude)

    # Check that the inputs are of the same shape
    if isinstance(conductivity, np.ndarray):
        if (
            conductivity.shape != temperature.shape
            or conductivity.shape != pressure.shape
            or conductivity.shape != latitude.shape
            or conductivity.shape != longitude.shape
        ):
            raise ValueError(
                "Conductivity, temperature, pressure, latitude, and longitude must have the same shape."
            )

    # Check that the latitude is beetwen -90 and 90
    if isinstance(latitude, np.ndarray):
        if np.any(latitude < -90) or np.any(latitude > 90):
            raise ValueError("Latitude must be between -90 and 90 degrees.")
    else:
        if latitude < -90 or latitude > 90:
            raise ValueError("Latitude must be between -90 and 90 degrees.")

    # Check that the longitude is beetwen -360 and 360
    if isinstance(longitude, np.ndarray):
        if np.any(longitude < -360) or np.any(longitude > 360):
            raise ValueError("Longitude must be between -360 and 360 degrees.")
    else:
        if longitude < -360 or longitude > 360:
            raise ValueError("Longitude must be between -360 and 360 degrees.")
    practical_salinity = gsw.SP_from_C(conductivity, temperature, pressure)
    absolute_salinity = gsw.SA_from_SP(
        practical_salinity, pressure, longitude, latitude
    )
    return absolute_salinity

Calculates pressure in dbars from depth in meters.

Parameters:

Name Type Description Default
depth Union[float, ndarray, List[float]]

Depth in meters.

 required
latitude Union[float, ndarray, List[float]]

Latitude in degrees. Defaults to None.

 None

Returns:

Name Type Description
pressure Union[float, ndarray]

Pressure in dbars.

Raises:

Type Description
ValueError

If the latitude is not between -90 and 90 degrees.
Source code in navlib/environment/seawater.py 
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def depth2pressure(
    depth: Union[float, np.ndarray, List[float]],
    latitude: Union[float, np.ndarray, List[float]] = None,
) -> Union[float, np.ndarray]:
    """
    Calculates pressure in dbars from depth in meters.

    Args:
        depth (Union[float, np.ndarray, List[float]]): Depth in meters.
        latitude (Union[float, np.ndarray, List[float]], optional): Latitude in degrees. Defaults to None.

    Returns:
        pressure (Union[float, np.ndarray]): Pressure in dbars.

    Raises:
        ValueError: If the latitude is not between -90 and 90 degrees.
    """
    # Convert to numpy arrays
    if isinstance(depth, list):
        depth = np.array(depth)
    if isinstance(latitude, list):
        latitude = np.array(latitude)

    # Check inputs type
    if not isinstance(depth, (np.ndarray, float)):
        raise TypeError("Depth must be a float or an array.")
    if latitude is not None and not isinstance(latitude, (np.ndarray, float)):
        raise TypeError("Latitude must be a float or an array.")

    # Check shape of inputs if they are numpy arrays
    if isinstance(depth, np.ndarray):
        depth = depth.squeeze()
        if depth.ndim > 1:
            raise ValueError("Depth must be a 1D array.")
    if latitude is not None and isinstance(latitude, np.ndarray):
        latitude = latitude.squeeze()
        if latitude.ndim > 1:
            raise ValueError("Latitude must be a 1D array.")

    # If latitude is not provided, set it to 0
    if latitude is None:
        latitude = 0 if isinstance(depth, float) else np.zeros_like(depth)
    elif isinstance(latitude, float) and isinstance(depth, np.ndarray):
        latitude = np.full_like(depth, latitude)

    # Check that the inputs are of the same shape
    if isinstance(depth, np.ndarray):
        if depth.shape != latitude.shape:
            raise ValueError("Depth and latitude must have the same shape.")

    # Check that the depth is negative
    if isinstance(depth, np.ndarray):
        if np.any(depth > 0):
            raise ValueError("Depth must be negative.")
    else:
        if depth > 0:
            raise ValueError("Depth must be negative.")

    # Check that the latitude is beetwen -90 and 90
    if isinstance(latitude, np.ndarray):
        if np.any(latitude < -90) or np.any(latitude > 90):
            raise ValueError("Latitude must be between -90 and 90 degrees.")
    else:
        if latitude < -90 or latitude > 90:
            raise ValueError("Latitude must be between -90 and 90 degrees.")

    return gsw.p_from_z(depth, latitude)